Fiber optic spool

Abstract: A spool (10) for filamentary material such as optical fibers and others consists of two members (20, 22) which are locked together to form a drum with two opposed flanges (14, 16) defining a winding space. The two members (20, 22) may be separated to allow material wound on the drum to be removed at will. After the material is removed, the two parts may be locked again making the spool reusable.

Description: BACKGROUND OF THE INVENTION a. Field of Invention This invention pertains to a spool for holding wires, cables or optical fibers, and more specifically to a spool which can be separated at will into two parts. b. Description of the Prior Art Filamentary materials such as wires, cables, optical fibers, are kept for ease of handling on a spool consisting of a tubular drum having two opposed ends and two flanges affixed to said barrel at the respective ends and extending radially outwardly therefrom. One end of the elongated material is secured on the drum and the elongated material is then wound thereon. Once the spool has been transported to the cabling site, the material is paid off from the spool until a preselected length has been reached. A problem with existing spools relates to the manner in which remainders are removed. The elongated material is provided in various lengths which normally exceed the amount of material actually required. For example, while a spool may hold 110 km of optical cable, of which only a 100 km of optical fiber may be actually required. After a desired amount of material, for example about 100 km, is removed from the spool the remainder (i.e. about 10 km) is usually too short for most applications and must be discarded. However, this remainder must still be removed form the spool if the spool is to be reused. In prior art spools, the remainders could be removed by paying it off the spool, a very time consuming operation. Moreover, this was also unsatisfactory because it may require equipment which may be used more efficiently elsewhere, and results in a length of unwound material which is difficult to handle. More frequently the remainder was simply cut off, however it was almost impossible to cut each strand or coil without damaging the barrel, especially if a relatively thin material is involved, such as an optical fiber. FR 2 204 188 A describes a spool with the features of the preamble of claim 1. OBJECTIVES AND SUMMARY OF THE INVENTION An objective of the present invention is to provide a spool for winding filamentary material, wherein said material is separable into two pieces to permit the removal of remainders from the spool. Another objective is to provide a spool made of two pieces, said pieces being identical for ease of replacement. A further objective is to provide a spool which may be made by a single cavity injection molding. Other objectives and advantages of the invention shall become apparent from the following description. The invention provides a spool comprising a first member and a second member, each of said spool members comprising a cylindrical wall, an inner end wall and an outer flange, and interlocking means provided on said inner end walls for selectively interlocking said members to define a winding space for holding filamentary material, said interlocking means being capable of being selectively released to disengage said members and allow at least a portion of said material to be removed therefrom, said interlocking means including at least one male member and at least one female member formed on each inner end wall, said at least one male member being adapted to engage said at least one female member of the other respective spool member upon relative rotation of said spool members, characterised in that said interlocking means further comprises a plurality of removable locking pins adapted to be inserted and retained in holes also provided in said inner end walls, the arrangement being such that said locking pins prevent said spool members from turning with respect to each other and disengaging until said pins are removed. Thus, briefly, a spool for filamentary materials particularly optical fibers, consists of a drum and two flanges disposed at the axial ends of the drum to define a toroidal winding space. The spool is made preferably of two identical members, each having a cylindrical wall and one flange, the members being formed so that when they are placed in an abutting relationship, the cylindrical surfaces form the drum. Interlocking means are used to selectively secure the two members together. The flanges may be tapered or perpendicular to the barrel. The interlocking means may be disengaged to allow the two members to separate for removal of the material wound thereon. A resilient sleeve may be mounted on the drum for the protection of the wound material. Further particular embodiments are defined in the dependent claims. BRIEF DESCRIPTION OF THE FIGURES Figure 1 shows a side elevational view of a spool constructed in accordance with this invention; Figure 2 shows a cross-sectional view of the spool taken along line 2-2 in Figure 3 with the protective sleeve omitted; Figure 3 shows an end view of the spool of Figure 2; Figure 4 show an end view of a spool member for the spool of Figures 2-3; Figure 5 is an enlarged section of the end view of Figure 4 showing the interlock means; Figures 5A and 5B show blown-up details of the section of Figure 5; Figure 6 shows a sectional view of the interlock means of Figure 5; Figure 7 shows a bottom view of the interlock means of Figures 5-6; Figures 8A and 8B show an enlarged view of two spool members before and after engagement respectively; Figures 9A and 9B show a sectional view and an end view respectively of a locking pin for the spool of Figure 2; Figure 9C shows a blown-up detail of the pin of Figure 9A; Figure 10 shows an exploded view of the spool; Figure 11 shows the spool of Figure 1 wound with a filamentary material; Figure 12 shows a cross sectional view of a spoke for the spool members taken along line 12-12 in Figure 4. DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, a spool 10 constructed in accordance with this invention consists of a cylindrical drum 12 and two frustoconical flanges 14, 16 disposed coaxially with the drum 12 as shown. The drum 12 may be optionally covered with a sleeve 18 made of a resilient material such as a polyethylene foam. This material is commercially available in various sizes which can be cut to a rectangular sheet and its ends can be joined by solvent welding or other means to form the sleeve commercial. The spool is made of a high impact plastic material such as polystyrene or abs, preferably by injection molding using a single cavity injection mold. As best seen in Figure 2, the spool 10 is made of two identical members 20, 22 joined as described in more detail along a plane Y-Y normal to the longitudinal axis X-X of the spool 10. Member 20 consists of an outer section 24 and a central section 54. Outer section 24 includes a cylindrical wall 26 which forms one half of the drum 12 and terminating on the left side with a circular end piece 28. Opposite piece 28, wall 26 is terminated by flange 16 and an axially extending circular lip 30. Preferably a small portion 32 of flange 16 extends radially outwardly of wall 26 before the flange starts angling axially. The radial dimension of this portion 32 is equal in length to the thickness of sleeve 18. As seen in Figures 3 and 4 flange 16 has two diametrically opposed rectangular slots 34, 36. Details of end piece 28 are shown in Figure 4. It consists of a circular outer rim 38. This rim 38 is formed with a plurality of arcuate depressions 40 alternating with arcuate raised areas or teeth 42. Radially inwardly of rim 38 is a central hub 46 having the shape of a cylindrical sleeve extending axially as shown in Figure 2. Hub 46 is connected to rim 38 by a plurality of radial spokes 48. As best seen in Figure 2, the hub 46 is connected to each of the spokes 48 by a triangular wall 50 for reinforcement. Preferably, the spokes are not equidistant from each other but instead they are separated by angles ranging from 30° to 60°. However, the spokes are symmetrically arranged with respect to a vertical axis Z-Z passing through the two flange slots 34, 36. The spokes have a generally Y-shaped cross-section, with the two arms 47, 49 of the Y being shown in Figure 12. Four of the spokes are provided with an enlarged D-shaped land area 52 used for interlocking the spool members 20, 22 as described below. The central section 54 (Figure 2) consists of a hollow shaft 56 terminated on the right side with a circular end 58. A plurality of triangular walls 60 are used to brace the shaft 56 against end 58. At its outer perimeter, end 58 is provided with a cylindrical section 62 extending coaxially with shaft 56. A portion of end 58 extend radially outwardly of wall 62 to form a small flange 64. As seen in Figure 3, end 58 is formed with a plurality of circular holes 66 as well as three oval holes 68, all the holes 66, 68 being disposed about sleeve 56. A shallow rectangular area 70 on end 58 is provided for holding a label identifying the spool and/or its contents. The two sections 24, 54 are made separately using single cavity molding techniques. To assemble the two sections 24, 54, the shaft 56 is axially inserted into the hub 44, while at the same time cylindrical section 62 slides telescopically over lip 30 until it reaches the section 32 of flange 16. In this position, the shaft 56 is joined to the hub 44 and wall 62 is joined to lip 30 by using any well known means such as by solvent welding or the use of an adhesive. Referring now to Figures 5-8, D-shaped land area 52 is formed with a circular hole 80 disposed in the vicinity of an end of spoke 48. Underneath hole 80, as viewed in Figure 5, there is a generally rectangular hole 82. To the left of hole 82 is a slightly smaller rectangular hole 84. In the view of Figure 5, hole 84 is partially covered by an L-shaped tongue 86 (Figure 6) having a first section 88 extending normally away from land area 52 and a second section 90 extending in parallel to land area 52 and connected to one end of section 88. The opposite end of section 90 is tapered as at 92. In addition, one side of section 90 is formed with slight groove 94 (Figures 5, 5A). As shown in Figure 6, land area 52 is reinforced by two braces 96, 98 extending to and are integral with cylindrical wall 26. On the right side of hole 82, as seen in Figures 5 and 5B, there is a boss 100 extending axially inwardly into member 52 in a direction opposite to tongue 86. Boss 100 has a cross sectional shape which is at least partially complementary to groove 94. As previously mentioned members 20 and 22 are preferably substantially identical. Referring to Figure 10, the spool 10 is assembled as follows. First sleeve 18 is inserted over member 22. Next, member 20 is inserted into sleeve 18 until it abuts member 22 and the two members are then engaged to each other to form the spool 10. For this purpose the two members are held in an interengaged position by the components of the land areas on the abutting end pieces as shown in detail in Figures 8A and 8B. In Figures 8A and 8B for the sake of clarity the elements of member 22 are identified by a prime symbol (') to differentiate them from the identical elements of member 20. The two members 20, 22 are engaged by first positioned side by side so that their hubs are aligned along common axis X-X and the spokes 48 of member 22 are disposed adjacent to each other and offset angularly by a small angle to permit the tongue of one member to enter into the rectangular holes of the other member by advancing one of the members toward the other along said common axix until the two end pieces are in contact with each other. In this configuration, the teeth 42 of one member (Figure 4) are inserted into the corresponding depressions 40 of the other member. The depressions are slightly longer 40 than the teeth 42 to allow the members 20, 22 to turn with respect to each other by a small angle. In Figure 8A, tongue 86 has been advanced in direction indicated by arrow A so that its section 90 has passed through hole 82'. At the same time tongue 86' is slipped into hole 82 as shown. Next, the two members 20, 22 are rotated with respect to each other about axis X-X to cause the spokes of the members to be precisely aligned with each other. This rotation causes the land area 52 to move with respect to land area 52' in the direction B in Figure 8A. As a result, section 90 of tongue 86 moves behind area 52' until its groove 94 snaps into engagement with boss 100', as shown in Figure 8B. Similarly hole 82 moves to engage tongue 86'. The final position of the tongues can be seen through holes 68 in Figure 3. Since there are at least three land areas 52 disposed angularly about the hub 56, the two members 20, 22 are solidly interengaged against both axial and radial forces. However, the spool 10 may be subjected to severe shaking especially if it is dropped, which may cause its members to separate. In order to prevent such an inadvertent separation, the spool is provided with locking pins, such as locking pin 102 shown in Figures 9A and 9B. Pin 102 is formed of a body 104 which is preferably fluted so that it forms an X-shaped cross section as seen in Figure 9B. At one end, a round head 106 is attached to the body, said head having an outer diameter larger than the inner diameter of hole 80 (Figure 5). Adjacent to its free end, body 104 is formed with a circumferential groove 108. Extending radially outwardly of groove 108 are a plurality of fins 110. As seen in Figures 9A and 9B, the fins extend radially outwardly of body 104. After the two members 20, 22 are interengaged, as discussed above, at least two pins 102 are introduced into the member 20 through holes 68 and then inserted through holes 80. The distance between fins 110 and head 106 is equal to the thickness of the land areas 52, 52' so that as body 104 passes through the holes of the end pieces, the fins 110 first bend radially inwardly and then when they are through, they snap outwardly to maintain the pins in place. The pins 102 prevent the members 20, 22 from turning with respect to each other and hence insure that they remain interengaged until the pins 102 are removed. After the spool 10 has been assembled, a filamentary material is wound on it as shown on Figure 11. The main body 120 of the material is wound between the flanges 14, 16 as shown. However, for some materials, such as for example optical fibers, both ends of the material must be accessible for testing. For these types of material, the inner end 122 of the material is first wound on the cylindrical wall 62 which forms a secondary winding surface disposed between the main flange 16 and auxiliary flange 64, shown in detail Figure 2. After a predetermined length of material (for example about 10m for an optical fiber) is on wall 62, the material is past through slot 34 or 36 and is then wound on sleeve 18 until the spool is full as shown in Figure 11. As described above, the spool is constructed and arranged so that the wall 62 and the outer surface of the sleeve 18 are substantially even to insure that the filamentary material winds properly on the spool without any bends. The spool with the wound material is transported to the cabling site where a predetermined amount of material is removed therefrom. If the remainder left on the spool is unusable, or if the remainder must be removed for any other reason, the two spool members are easily separated by removing pins 102 and turning one of the spool members until the two spool members are disengaged. The spool members are then separated and the remainder is removed in a neat and manageable coil. This remainder coil is discarded or put to other use, while the spool can be reassembled and shipped back to a manufacturing facility to be reused. The present invention has a certain features which are particularly advantageous, especially for optical fibers. Preferably the spool 10 is made of plastic material which has a thermal expansion coefficient usually larger than the coefficient of some of the material to be wound i.e., the coefficient of optical fibers. Therefore if the material is wound directly ont the drums, a rise in the ambient temperature causes the spool body expands more than the material wound thereon which in turn may damage the optical fiber by changing its index of refraction. The sleeve 18 being resilient absorbs the expansion of the drum thereby preventing damage to the material. In addition, the sleeve cushions the wound material from shocks and vibrations. Finally, the sleeve prevents the material from sliding on the drum as it is being wound or transported. The sleeve 18 is made of a relatively inexpensive material so that if it is damaged, it is easily replaced. Of course for some filamentary material the sleeve may be omitted. Similarly, since the two spool members are identical, they can be easily manufactured and if one is damaged, it is readily replaceable. Obviously numerous modifications can be made to this invention without departing from its scope as defined in the appended claims.

Claims: A spool comprising a first member (20) and a second member (22), each of said spool members comprising a cylindrical wall (26), an inner end wall (28) and an outer flange (16), and interlocking means provided on said inner end walls for selectively interlocking said members to define a winding space for holding filamentary material, said interlocking means being capable of being selectively released to disengage said members and allow at least a proportion of said material to be removed therefrom, said interlocking means including at least one male member (86) and at least one female member (82) formed on each inner end wall, said at least one male member being adapted to engage said at least one female member of the other respective spool member upon relative rotation of said spool members, characterised in that said interlocking means further comprises a plurality of removable locking pins (102) adapted to be inserted and retained in holes (80) also provided in said inner end walls (28), the arrangement being such that said locking pins (102) prevent said spool members (20, 22) from turning with respect to each other and disengaging until said pins are removed. The spool of claim 1 further comprising a sleeve disposed about said cylindrical walls. The spool of claim 1 wherein said members are identical. The spool of claim 1 wherein each said locking pin (102) comprises a head (106) to which is attached a fluted body (104). The spool of claim 4 wherein each said locking pin (102) comprises a groove (108) that extends circumferentially about said body (104). The spool of claim 5 wherein each said locking pin (102) comprises a plurality of fins (110) which extend radially outwardly of said body (104). The spool of claim 1 further comprising annular flanges disposed at said outer ends. The spool of claim 7 wherein at least one of said members if formed with a secondary winding surface extending axially away from a corresponding annular flange. The spool of claim 8 wherein said secondary winding surface is bounded between said annular flange and an auxiliary flange axially spaced from said annular flange. The spool of claim 9 wherein said annular flange is formed with slots connecting said auxiliary surface to said winding space. The spool of claim 7 wherein each said member includes an end wall forming said flanges. The spool of claim 11 wherein at least one of said members has an outer cylindrical wall for forming a secondary winding surface separate from said winding space. The spool of claim 1 wherein said male member engages said female member by rotating one of said spool members. The spool of claim 1 further comprising a shock absorbing sleeve disposed in said winding space for protecting filamentary material disposed in said winding space.

Inventors: BOYLES LELAND HUBERT, DESROSIERS VICTOR JOSEPH, FAZIO ROBERT VINCENT, PIERRO STEVEN WILLIAM, PINO SANTO, TREFZGER RONALD TRACY, WILKINSON JAMES RICHARD, BOYLES, LELAND HUBERT, DESROSIERS, VICTOR JOSEPH, FAZIO, ROBERT VINCENT, PIERRO, STEVEN WILLIAM, PINO, SANTO, TREFZGER, RONALD TRACY, WILKINSON, JAMES RICHARD
Applicants: CRELLIN INC, CRELLIN, INC.
Application year: 1994
Main classification: B65H75
IPC codes: B65H75